docs: def _start_priority_containers(self, groups, group_orders, tool_d):
          """ Select containers based on priorities to start """
          vent_cfg = Template(self.path_dirs.cfg_file)
          cfg_groups = vent_cfg.option('groups', 'start_order')
          if cfg_groups[0]:
              cfg_groups = cfg_groups[1].split(',')
          else:
              cfg_groups = []
          all_groups = sorted(set(groups))
          s_conts = []
          f_conts = []
          # start tools in order of group defined in vent.cfg
          for group in cfg_groups:
              # remove from all_groups because already checked out
              if group in all_groups:
                  all_groups.remove(group)
              if group in group_orders:
                  for cont_t in sorted(group_orders[group]):
                      if cont_t[1] not in s_conts:
                          s_conts, f_conts = self._start_container(cont_t[1],
                                                                   tool_d,
                                                                   s_conts,
                                                                   f_conts)
          # start tools that haven't been specified in the vent.cfg, if any
          for group in all_groups:
              if group in group_orders:
                  for cont_t in sorted(group_orders[group]):
                      if cont_t[1] not in s_conts:
                          s_conts, f_conts = self._start_container(cont_t[1],
                                                                   tool_d,
                                                                   s_conts,
                                                                   f_conts)
          return (s_conts, f_conts)